Effects of fodder tree leave supplementation for basal rice straw diet on rumen ammonia, pH, and degradation characteristics in sheep

Abstract

Fodder tree leaves (FTLs) contain high levels of protein, vitamins, and minerals that play a major role in enhancing roughage intake by ruminants, thus improving low-quality roughage utilization. The study sought to measure the rumen degradation characteristics, pH, and ammonia N concentration of sheep fed rice straw (RS) and supplemented with FTLs. Four forest-type rumen-fistulated rams of an average weight of 19.0±1.2 kg were randomly assigned to one of four treatments in a 4 × 4 Latin Square design. Treatment diets consisted of urea-ammoniated straw (UAS; control), RS+100% Leucaena leucocephala (L), RS+100% Samanea saman (S), and RS+50% L+50% S (LS). Data obtained were subjected to the Glimmix procedure of SAS (2016) and significant means were separated using Tukey’s test at (P<0.05). Treatments differed significantly (P<0.001) in the quantity of readily soluble materials (a), rate of degradation (c), and a potentially degradable fraction (P) with LS recording the highest a, c, and P among the treatments. Ruminal pH and ammonia concentrations differed significantly (P<0.0001) among the treatments. Overall mean rumen pH values obtained ranged from 6.44 in UAS to 6.72 in the S-supplemented diet whereas mean rumen ammonia values ranged from 4.59 mg/100 ml in sheep fed UAS diet to 9.15 mg/L in sheep fed L diet. The pH values obtained imply that the experimental diets could improve rumen fermentation and, hence, serve as good sources of feed for ruminants. The rumen DM degradation values indicated that sufficient amounts of DM would be degraded over a period of time, thus releasing substantial quantities into the small intestines for digestion to provide essential nutrients needed for better animal performance. The rumen ammonia values obtained were higher than the minimum values recommended for optimal microbial activity for animals fed lignocellulosic materials. This indicated that such FTLs could be utilized for moderate animal performance, especially during the dry seasons when natural pastures are qualitatively and quantitatively poor.